Direct Detection of Dark Matter

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1 Direct Detection of Dark Matter ENTApP Dark Matter Visitor's Program DESY, Hamburg, 2008 Mitsuru Kakizaki (Bonn) Chung-Lin Shan (Bonn) David G. Cerdeño (Madrid)

2 Contents Direct searches for WIMPs Brief update on the experimental situation. spin-independent vs. spin-dependent interactions Theoretical frameworks for WIMPs Cerdeño Lightest SUSY particle (LSP), e.g., the NEUTRALINO, the SNEUTRINO Little Higgs Models (LTP) Lightest Kaluza-Klein particle (LKP) Kakizaki How can we identify the WIMP? Strategies for discriminating WIMP DM candidates Shan

3 Detecting WIMP dark matter

Luminous (visible) matter is insufficient to account for the observed effects.

4 Motivation for Dark Matter Introduction The motivation for dark matter arises from gravitational effects in astronomical observations at various scales. Luminous (visible) matter is insufficient to account for the observed effects. At the galactic scale: Rotation curves of spiral galaxies Gas temperature in elliptic galaxies Coma Cluster Clusters of galaxies Peculiar velocities Gas temperature (X-ray measurements) Gravitational lensing

5 WIMP direct detection The direct detection of Dark Matter can take place through their interaction with nuclei inside a detector The nuclear recoiling energy is measured Ionization on solids Ionization in scintillators (measured by the emmited photons) Temperature increase (measured by the released phonons) Problems Very small interaction rate Large backgrounds (experiments must be deep underground) Uncertainties in the DM properties in our galaxy

6 WIMP direct detection The direct detection of WIMPS can take place through their elastic scattering with nuclei inside a detector The nuclear recoiling energy is measured Ionization on solids Ionization in scintillators (measured by the emmited photons) Temperature increase (measured by the released phonons) Modern and projected detectors use a combination of these techniques Ionization + phonons: CDMS, EDELWEISS Ionization + scintillation: ZEPLIN II, III, XENON Scintilation + phonons: CRESST II, ROSEBUD

7 Dark matter related experiments around the world (2007) (P.B. Cushman 07) CAB

8 Dark matter related experiments around the world (2007) CAB

9 WIMP-nucleus interaction The interaction of a generic WIMP with nuclei has several contributions Axial-Vector L A ~ Scalar Adds incoherently L S ~ SPIN-DEPENDENT SPIN-INDEPENDENT (Nucl. Angular mom) (Nucleon #) Vector L V ~ Adds coherently Only for non-majorana WIMPs SPIN-INDEPENDENT

10 Spin-independent cross section Detectability Most of the experiments nowadays are mostly sensitive to the scalar (spinindependent) part of the WIMP-nucleon cross section (using, e.g., with Iodine or Germanium). (Dominant for nuclei with A 20) How large can the WIMP detection cross section be? Which dark matter candidates could account for a hypothetical WIMP detection? DAMA CRESST Edelweiss ZEPLIN Gedeon CDMS CDMS XENON10 Super CDMS Calculate the theoretical predictions for WIMP-nucleus cross section XENON 1T

11 Heavyweights... Two heavyweights have taken over in the last years... CDMS XENON CAB

Direct detection experiments CDMS Brown U., Caltech. Case Western Reserve U., FNAL, MIT, RWTH-Aachen, Santa Clara U. Stanford, Berkeley, Santa Barbara, U. Of Colorado, U. Of Florida, U.

12 Direct detection experiments CDMS Brown U., Caltech. Case Western Reserve U., FNAL, MIT, RWTH-Aachen, Santa Clara U. Stanford, Berkeley, Santa Barbara, U. Of Colorado, U. Of Florida, U. Of Minessotta. Soudan Underground Laboratory Initiated 2000 Simultaneous measurement of ionization and temperature increase. Sep. 2005: 6x250g Ge and 6x100g Si solid state detectors operated at 50 mk CAB

13 Direct detection experiments CDMS Brown U., Caltech. Case Western Reserve U., FNAL, MIT, RWTH-Aachen, Santa Clara U. Stanford, Berkeley, Santa Barbara, U. Of Colorado, U. Of Florida, U. Of Minessotta. Soudan Underground Laboratory Initiated 2000 Simultaneous measurement of ionization and temperature increase. Sep. 2005: 6x250g Ge and 6x100g Si solid state detectors operated at 50 mk CAB

14 Direct detection experiments XENON Columbia U., Brown U., Rice U., Case Western Reserve U., RWTH-Aachen U., Yale U., Lawrence Livermore National Lab., LNGS, U. Of Coimbra Gran Sasso National Laboratory (LNGS) Measurement of scintillation and ionization CAB

Direct detection experiments XENON Columbia U., Brown U., Rice U., Case Western Reserve U., RWTH-Aachen U., Yale U., Lawrence Livermore National Lab., LNGS, U.

15 Direct detection experiments XENON Columbia U., Brown U., Rice U., Case Western Reserve U., RWTH-Aachen U., Yale U., Lawrence Livermore National Lab., LNGS, U. Of Coimbra Gran Sasso National Laboratory (LNGS) Measurement of scintillation and ionization June 2007: XENON10 results from a 10 month WIMP search run CAB

16 Direct detection experiments CDMS Brown U., Caltech. Case Western Reserve U., FNAL, MIT, RWTH-Aachen, Santa Clara U. Stanford, Berkeley, Santa Barbara, U. Of Colorado, U. Of Florida, U. Of Minessotta. Soudan Underground Laboratory Initiated 2000 Simultaneous measurement of ionization and temperature increase. Feb. 2008: 19x250g Ge and 11x100g Si solid state detectors operated at 50 mk (18 additional detectors since 2006, improved cryogenic stability, increased exposure) NEW DATA FROM 15 DETECTORS CAB

17 Spin-dependent cross section Detectability On the other hand, the sensitivity of these experiments for the spin-dependent part of the WIMP-nucleus cross section is not that big Neutralino Savage, Gondolo, Freese 06

18 Spin-dependent cross section Detectability On the other hand, the sensitivity of these experiments for the spin-dependent part of the WIMP-nucleus cross section is not that big Neutralino Savage, Gondolo, Freese 06

Direct detection experiment PICASSO U. degli Studi di Pavia, INFN, LNGS, U. degli Studi dell Aquila, Napoli, Padova, Princeton U., IFJ PAN Krakow, SNOLAB, Sudbury (Canada) 4.

19 Direct detection experiment PICASSO U. degli Studi di Pavia, INFN, LNGS, U. degli Studi dell Aquila, Napoli, Padova, Princeton U., IFJ PAN Krakow, SNOLAB, Sudbury (Canada) 4.5l modules with 80g of active mass of C 4 F 10. Droplets are suspended in elastic polymer. Feb. 2005: Results Presently PICASSO is installing a new experiment with 32 detector modules and with an active mass of 2.6 kg CAB

COUPP (Chicagoland Observatory for Underground Particle Physics) Detectability COUPP A vessel containing CF 3 I, that can be superheated to respond to very low

20 COUPP (Chicagoland Observatory for Underground Particle Physics) Detectability COUPP A vessel containing CF 3 I, that can be superheated to respond to very low energy nuclear recoils like those expected from WIMPs while being totally insensitive to minimum ionizing particles

21 COUPP Detectability Detection of single bubbles in a superheated liquid, induced by high de/dx nuclear recoils in heavy liquid bubble chambers Choice of three triggers: pressure, acoustic, motion Stereo view of a typical event in 2 kg chamber

22 Experimental Timeline (P.B. Cushman 07) CAB

23 Experimental Timeline LHC (P.B. Cushman 07) CAB

24 Experimental Timeline LHC (P.B. Cushman 07) CAB

25 What do we (theorists) need to provide? In order to determine the feasibility of direct detection of WIMP DM Evaluate the theoretical predictions for the WIMP-nucleon scattering cross section Lightest Supersymmetric Particle (Neutralinos) Lightest Kaluza-Klein Particle and compare the with experimental sensitivities in both the spin-dependent and independent channels Compatibility with an LHC hypothetical signal Compatibility with indirect DM searches

26 Theoretical frameworks for WIMPs Lightest neutralino, sneutrino (SUSY theories) LTP (little Higgs models) Lightest KK particle (extra dimensions)

So WHAT is the Dark Matter? We have a good idea of what we are looking for: However, the number of suspects is large, all postulated in modern Particle Physics.

27 So WHAT is the Dark Matter? We have a good idea of what we are looking for: However, the number of suspects is large, all postulated in modern Particle Physics. Axions with a small mass m a 10-5 ev Weakly Interacting Massive Particles (WIMPs) Lightest Supersymmetric Particle Lightest Kaluza-Klein Particle SIMPs, CHAMPs, SIDM, WIMPzillas, Scalar DM, Light DM NEW PHYSICS BEYOND THE STANDARD MODEL OF PARTICLE PHYSICS

28 Lightest Supersymmetric Particle R-parity is usually invoked in Supersymmetric theories in order to forbid new baryon and lepton number violating interactions at the weak scale The LSP is stable in SUSY theories with R-parity. Thus, it will exist as a remnant from the early universe and may account for the observed Dark Matter.

29 Lightest Supersymmetric Particle Introduction The LSP is stable in SUSY theories with R-parity. Thus, it will exist as a remnant from the early universe and may account for the observed Dark Matter. In the MSSM, the LSP can be Lightest squark or slepton: charged and therefore excluded by searches of exotic isotopes Lightest sneutrino: They annihilate very quickly and the regions where the correct relic density is obtained are already experimentally excluded Lightest neutralino: WIMP Gravitino: Present in Supergravity theories. Can also be the LSP and a good dark matter candidate Axino: SUSY partner of the axion. Extremely weak interactions

30 Lightest Supersymmetric Particle Introduction The LSP is stable in SUSY theories with R-parity. Thus, it will exist as a remnant from the early universe and may account for the observed Dark Matter. In the MSSM, the LSP can be Lightest sneutrino: Possible in extensions of the MSSM by reducing its mixing with the Z boson: WIMP Lightest neutralino: WIMP

31 The neutralino in the MSSM Detectability Neutralinos in the MSSM are physical superpositions of the bino and wino and Higgsinos The detection properties of the lightest neutralino depend on its composition

32 Spin-independent cross section Contributions from squark- and Higgs-exchanging diagrams: Squark-exchange Higgs-exchange It is the leading contribution, and increases when Z The Higgsino components of the neutralino increase The Higgs masses decrease

33 Neutralino in the MSSM Detectability In a General Supergravity theory, sizable detection cross sections can be obtained when non-universal soft parameters are taken into account. XENON10 XENON10 Very light Bino-like neutralinos with masses ~10 GeV. Heavy Higgsino-like neutralinos with masses ~500 GeV. (S.Baek, D.G.C., G.Y.Kim, P.Ko, C.Muñoz 05)

34 Neutralino in the MSSM Detectability Which areas of the parameter space are more likely, in view of the various experimental constraints? For example, in the CMSSM (Trotta, Ruiz de Austri, Roszkowski 06)

Neutralino in the MSSM Detectability In a General Supergravity theory, sizable detection cross sections can be obtained when non-universal soft parameters are taken into account.

35 Neutralino in the MSSM Detectability In a General Supergravity theory, sizable detection cross sections can be obtained when non-universal soft parameters are taken into account. XENON10 S o m e r e g i o n s o f t h e parameter space within the sensitivity of projected DM experiments (Remember, though, that theoretical errors can be sizable) (J.R.Ellis, K.A.Olive, Y.Santoso, V.Spanos 05)

36 Neutralino in the MSSM Detectability In a General Supergravity theory, sizable detection cross sections can be obtained when non-universal soft parameters are taken into account. XENON10 S o m e r e g i o n s o f t h e parameter space within the sensitivity of projected DM experiments (Remember, though, that theoretical errors can be sizable) (J.R.Ellis, K.A.Olive, Y.Santoso, V.Spanos 05)

37 Spin-dependent cross section Detectability Contributions from squark- and Z-exchanging diagrams: Squark-exchange Typically very small unless m q ~ m χ Z-exchange Z Leading contribution but has an upper bound: It also increases with the neutralino Higgsino components:

38 Spin-dependent searches Detectability Overall theoretical predictions in the MSSM: effmssm SUGRA inspired Enhancement of Z-exchange Through a decrease in the μ parameter ~ Enhancement of q-exchange (G.Bertone, D.G.C., J.I.Collar, B.Odom 07)

39 Sneutrino dark matter On the Standard MSSM: Pure left-handed sneutrino The sneutrino annihilation cross section is too large through its coupling with the Z boson (Ibáñez 84; Ellis, Hagelin, Nanopoulos, Olive 84; Hagelin, Kane, Rabi 84; Goodmann, Witten 85; Freese 86) ν ~ Z ν~

40 Sneutrino dark matter On the Standard MSSM: Pure left-handed sneutrino Too low relic density Too high detection cross section (C. Arina, N. Fornengo 07)

41 Sneutrino dark matter Beyond the Standard MSSM: Mixing left-handed/right-handed sneutrino Correct relic density Not excluded detection cross section (Grossmann, Haber 97; Arkani-Hamed, Hall, Murayama, Smith, Weiner 01; C. Arina, N. Fornengo 07)

42 Sneutrino dark matter Beyond the Standard MSSM: Models with lepton number violating terms and RH sneutrinos (the case for a see-saw neutrino mass). Correct relic density Large detection cross section (C. Arina, N. Fornengo 07)

43 Little Higgs Theories In a T-parity conserving model a heavy photon can play the role of WIMP dark matter (Arkani-Hamed, Cohen. Katz. Neson 02; J. Hubisz, P. Meade 03) (A. Birkedal, A. Noble, M. Perelstein, A. Spray 06)

44 Little Higgs Theories Identification In a T-parity conserving model a heavy photon can play the role of WIMP dark matter (A. Birkedal, A. Noble, M. Perelstein, A. Spray 06)

45 Identification of DM candidates Discriminating between DM candidates

46 Complementarity of DM searches Identification We are attacking the DM in various fronts: Direct Detection Indirect Detection S u p e r Heavy DM A x i o n - l i k e particles WIMP SuperWIMP Light DM R DDM LHC

47 Discriminating Neutralino vs LKP Identification Complementarity of spin-dependent and independent searches LSP LKP (G.Bertone, D.G.C., J.I.Collar, B.Odom 07)

48 Discriminating Neutralino vs LKP Identification The predictions from neutralino dark matter and KK dark matter can be within the reach of COUPP detector in some regions of the parameter space The hypothetical detection of a DM signal with a CF 3 I detector loosely constrains DM candidates. LKP LSP Using then a second detection fluid, C 4 F 10, with lower sensitivity to spinindependent couplings, reduces the number of allowed models. This can potentially be used to distinguish between LSP and LKP WIMPs. (G.Bertone, D.G.C., J.I.Collar, B.Odom 07)

49 Discriminating Neutralino vs LKP Identification The predictions from neutralino dark matter and KK dark matter can be within the reach of COUPP detector in some regions of the parameter space The hypothetical detection of a DM signal with a CF 3 I detector loosely constrains DM candidates. LSP LKP Using then a second detection fluid, C 4 F 10, with lower sensitivity to spinindependent couplings, reduces the number of allowed models. This can potentially be used to distinguish between LSP and LKP WIMPs. (G.Bertone, D.G.C., J.I.Collar, B.Odom 07)

50 Conclusions Dark Matter is a necessary ingredient in the present models of our Universe but we have not identified it yet. Experiments in the near future (direct, indirect, LHC) might have enough sensitivity to probe WIMP candidates. For certain classes of WIMPs a detector exclusively sensitive to one detection mode (spin-indepedent) may lack sensitivity to a large fraction of the parameter space Complementary information is needed from experiments which are sensitive to the spin-dependent part of the WIMP-nucleon cross section: The lightest neutralino The LKP in UED models The simultaneous direct measurement of axial and scalar couplings can help discriminating between WIMP candidates: e.g, Neutralino LSP and LKP in UED The possibility of operating experiments such as COUPP with a range of detection fluids allows a better determination of these couplings ENTApP, Matalascañas

51 ENTApP, Matalascañas Compatibility with DAMA result

52 Comparison with DAMA result Compatibility with DAMA observation? Savage, Gondolo, Freese ENTApP, Matalascañas

53 Comparison with DAMA result The predicted Spin-dependent cross section is insufficient to explain DAMA s result with neutralinos or KK dark matter LSP ENTApP, Matalascañas

54 Conclusions For certain classes of WIMPs a detector exclusively sensitive to one detection mode (spin-indepedent) may lack sensitivity to a large fraction of the parameter space Complementary information is needed from experiments which are sensitive to the spin-dependent part of the WIMP-nucleon cross section: The lightest neutralino can have a large spin-dependent detection cross section (Higgsino-like neutralinos or when squark masses are very close to the neutralino mass) The LKP in UED models can also have sizable axial couplings (due to q(1)- exhange diagrams) The simultaneous direct measurement of axial and scalar couplings can help discriminating between WIMP candidates: e.g, Neutralino LSP and LKP in UED The possibility of operating experiments such as COUPP with a range of detection fluids allows a better determination of these couplings ENTApP, Matalascañas

55 ENTApP, Matalascañas Projeted DM experiments

56 Projected and/or developing experiments These experiments and other projected ones are going to cover wider areas of the WIMP DM parameter space CAB

57 Direct detection experiments ArDM CIEMAT - ETH/Zurich U. Granada U. Sheffield - Soltan Institute Warszawa U. Zurich Initiated in 2004 Bi-phase 1 ton Argon detector with independent ionization and scintillation readout, to demonstrate the feasibility of a noble gas ton-scale experiment with the required performance to efficiently detect and sufficiently discriminate backgrounds for a successful WIMP detection. 1 st phase Placed at CERN, 2 nd phase Canfranc? CAB

58 Direct detection experiments WARP U. degli Studi di Pavia, INFN, LNGS, U. degli Studi dell Aquila, Napoli, Padova, Princeton U., IFJ PAN Krakow, Gran Sasso National Laboratory (LNGS) Detection in noble liquids. Started with Xenon, now switched to Argon (mostly due to previous experience with ICARUS) Inner double phase argon. When a particle interacts in the liquid region excitation and ionization occur. A primary scintillation signal due to disexcitation of argon is produced and detected by the photomultipliers positioned in the gaseous phase. If electric fields are applied, some ionization electrons produced in the interaction processes drift towards the gas phase, where they are accelerated in order to produce, through collisions with atoms, the emission of photons (proportional to ionization) in a secondary scintillation CAB

59 Direct detection experiments WARP U. degli Studi di Pavia, INFN, LNGS, U. degli Studi dell Aquila, Napoli, Padova, Princeton U., IFJ PAN Krakow, Gran Sasso National Laboratory (LNGS) Detection in noble liquids. Started with Xenon, now switched to Argon (mostly due to previous experience with ICARUS) Inner double phase argon. When a particle interacts in the liquid region excitation and ionization occur. Jan. 2007: Results based on a test chamber with 2.3 litre of liquid Ar (started 2004) Next step: 100 litres (140 Kg) detector CAB

60 Direct detection experiments ZEPLIN UCLA, UKDMC ( ), Texas A&M, CERN, Torino, Padova, UMSHN Mexico, CINVESTAV Mexico Boulby mine (UK) ZEPLINII: two-phase liquid Xe detector. Started 2005 First run results from Mar ZEPLINIII: Proposed a multi-ton liquid Xenon experiment. ZEPLINIV: 1ton upgrade of ZEPLINII CAB

Final results for EDELWEISS Measurement of ionization and

61 Direct detection experiments EDELWEISS CNRS, CEA, Karlsruhe, Dubna Modane Undergound Laboratory (LSM) 2005: Final results for EDELWEISS Measurement of ionization and phonons EDELWEISSII currently starting taking data CAB

62 Direct detection experiments ANAIS University of Zaragoza Canfranc Underground Laboratory Initiated 2000 ANAIS is a large mass scintillators experiment (10x10.7 kg NaI(Tl)) planned to look for an annual modulation in the WIMP signal kg prototype tested and started taking data in summer Aimed at background and threshold reduction CAB

experiment only sapphire (25 and 50 g) was used as absorber.

63 Direct detection experiments ROSEBUD University of Zaragoza, Institut d'astrophysique Spatiale, Orsay (IAS) Canfranc Underground Laboratory : First phase of the experiment only sapphire (25 and 50 g) was used as absorber : Second phase of the experiment operating bolometers of Germanium (67g), sapphire (50g) and Calcium Tungstate (54g) CAB

64 ENTApP, Matalascañas Non-universal soft masses

65 Non-universal soft terms Detectability Higgs-exchange Leading contribution. It can increase when Z The Higgsino components of the neutralino increase The Higgs masses decrease In terms of the mass parameters in the RGE m Hd 2 m 2 A 0 -μ 2 m Hu 2 Non-universal soft terms (e.g., in the Higgs sector) M GUT m Hu 2 m Hd 2

66 Non-universal soft terms In a more general SUGRA, non-universal scalar (and gaugino) masses allow more flexibility in the neutralino sector - Non-universal Higgses provide the most important variations - Non-universal gauginos can change the mass and composition of the lightest neutralino Appropriate non-universal schemes can lead to a large increase in the neutralino detection cross section.

67 ENTApP, Matalascañas The neutralino in the NMSSM

68 The neutralino in the NMSSM Detectability In the Next-to-MSSM there is a fifth neutralino due to the mixing with the singlino The lightest neutralino has now a singlino component

69 Spin-independent cross section Detectability Contributions from squark- and Higgs-exchanging diagrams: Squark-exchange Higgs-exchange It is the leading contribution, and increases when Z In the NMSSM very light Higgses (m h 20 GeV) can be obtained in the NMSSM. These have a large singlet component and avoid experimental constraints. The Higgs masses decrease

70 Neutralino in the NMSSM Detectability Very large detection cross sections can be obtained for singlino-line neutralinos This is due to the Higgs masses being very small. These results correspond to Higgses lighter than 70 GeV and mostly singlet-like (D.G.C., C.Hugonie, D.López-Fogliani, A.Teixeira, C.Muñoz 04) (D.G.C., E. Gabrielli, D.López-Fogliani, A.Teixeira, C.Muñoz 07)

singlino-line neutralinos Higgses lighter than 70

López-Fogliani, A.Teixeira, C.Muñoz 04) (D.G.C., E.

71 Neutralino in the NMSSM Detectability Very large detection cross sections can be obtained for singlino-line neutralinos Higgses lighter than 70 GeV and mostly singlet-like (D.G.C., C.Hugonie, D.López-Fogliani, A.Teixeira, C.Muñoz 04) (D.G.C., E. Gabrielli, D.López-Fogliani, A.Teixeira, C.Muñoz 07)

Theory of WIMPs. 4 th Patras Meeting DESY, Hamburg, David G. Cerdeño

Theory of WIMPs. 4 th Patras Meeting DESY, Hamburg, David G. Cerdeño Theory of WIMPs 4 th Patras Meeting DESY, Hamburg, 2008 David G. Cerdeño WIMPs: a Bestiary 4 th Patras Meeting DESY, Hamburg, 2008 David G. Cerdeño Contents WIMPs? Thermal production Direct searches for